/* Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.activiti.engine.impl.cmd;

import java.io.Serializable;

import org.activiti.bpmn.model.BpmnModel;
import org.activiti.bpmn.model.SubProcess;
import org.activiti.bpmn.model.ValuedDataObject;
import org.activiti.engine.ActivitiIllegalArgumentException;
import org.activiti.engine.ActivitiObjectNotFoundException;
import org.activiti.engine.DynamicBpmnConstants;
import org.activiti.engine.impl.DataObjectImpl;
import org.activiti.engine.impl.context.Context;
import org.activiti.engine.impl.interceptor.Command;
import org.activiti.engine.impl.interceptor.CommandContext;
import org.activiti.engine.impl.persistence.entity.ExecutionEntity;
import org.activiti.engine.impl.persistence.entity.TaskEntity;
import org.activiti.engine.impl.persistence.entity.VariableInstance;
import org.activiti.engine.impl.util.ProcessDefinitionUtil;
import org.activiti.engine.runtime.DataObject;
import org.activiti.engine.task.Task;

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.node.ObjectNode;

public class GetTaskDataObjectCmd implements Command<DataObject>, Serializable {

  private static final long serialVersionUID = 1L;
  protected String taskId;
  protected String variableName;
  protected String locale;
  protected boolean withLocalizationFallback;

  public GetTaskDataObjectCmd(String taskId, String variableName) {
    this.taskId = taskId;
    this.variableName = variableName;
  }

  public GetTaskDataObjectCmd(String taskId, String variableName, String locale, boolean withLocalizationFallback) {
    this.taskId = taskId;
    this.variableName = variableName;
    this.locale = locale;
    this.withLocalizationFallback = withLocalizationFallback;
  }

  public DataObject execute(CommandContext commandContext) {
    if (taskId == null) {
      throw new ActivitiIllegalArgumentException("taskId is null");
    }
    if (variableName == null) {
      throw new ActivitiIllegalArgumentException("variableName is null");
    }

    TaskEntity task = commandContext.getTaskEntityManager().findById(taskId);

    if (task == null) {
      throw new ActivitiObjectNotFoundException("task " + taskId + " doesn't exist", Task.class);
    }

    DataObject dataObject = null;
    VariableInstance variableEntity = task.getVariableInstance(variableName, false);

    String localizedName = null;
    String localizedDescription = null;

    if (variableEntity != null) {
      ExecutionEntity executionEntity = commandContext.getExecutionEntityManager().findById(variableEntity.getExecutionId());
      while (!executionEntity.isScope()) {
        executionEntity = executionEntity.getParent();
      }

      BpmnModel bpmnModel = ProcessDefinitionUtil.getBpmnModel(executionEntity.getProcessDefinitionId());
      ValuedDataObject foundDataObject = null;
      if (executionEntity.getParentId() == null) {
        for (ValuedDataObject dataObjectDefinition : bpmnModel.getMainProcess().getDataObjects()) {
          if (dataObjectDefinition.getName().equals(variableEntity.getName())) {
            foundDataObject = dataObjectDefinition;
            break;
          }
        } 
      } else {
        SubProcess subProcess = (SubProcess) bpmnModel.getFlowElement(executionEntity.getActivityId());
        for (ValuedDataObject dataObjectDefinition : subProcess.getDataObjects()) {
          if (dataObjectDefinition.getName().equals(variableEntity.getName())) {
            foundDataObject = dataObjectDefinition;
            break;
          }
        }
      }

      if (locale != null && foundDataObject != null) {
        ObjectNode languageNode = Context.getLocalizationElementProperties(locale, foundDataObject.getId(), 
            task.getProcessDefinitionId(), withLocalizationFallback);
        
        if (languageNode != null) {
          JsonNode nameNode = languageNode.get(DynamicBpmnConstants.LOCALIZATION_NAME);
          if (nameNode != null) {
            localizedName = nameNode.asText();
          }
          JsonNode descriptionNode = languageNode.get(DynamicBpmnConstants.LOCALIZATION_DESCRIPTION);
          if (descriptionNode != null) {
            localizedDescription = descriptionNode.asText();
          }
        }
      }

      if (foundDataObject != null) {
        dataObject = new DataObjectImpl(variableEntity.getName(), variableEntity.getValue(), foundDataObject.getDocumentation(), 
            foundDataObject.getType(), localizedName, localizedDescription, foundDataObject.getId());
      }
    }

    return dataObject;
  }
}
